Metamath Proof Explorer


Theorem ipodrscl

Description: Direction by inclusion as used here implies sethood. (Contributed by Stefan O'Rear, 2-Apr-2015)

Ref Expression
Assertion ipodrscl ( ( toInc ‘ 𝐴 ) ∈ Dirset → 𝐴 ∈ V )

Proof

Step Hyp Ref Expression
1 isipodrs ( ( toInc ‘ 𝐴 ) ∈ Dirset ↔ ( 𝐴 ∈ V ∧ 𝐴 ≠ ∅ ∧ ∀ 𝑥𝐴𝑦𝐴𝑧𝐴 ( 𝑥𝑦 ) ⊆ 𝑧 ) )
2 1 simp1bi ( ( toInc ‘ 𝐴 ) ∈ Dirset → 𝐴 ∈ V )